This study investigated the clinical benefit of using hypofractionated stereotactic body radiotherapy (SBRT) to manage spinal metastases in patients with cancer and to reduce cancer-related symptoms.
Cancer patients (n=149) with mechanically stable, non–cord-compressing, spinal metastases (n=166) were treated by SBRT in a phase I/II study. Patients received a total dose of 27–30 Gy, typically in three fractions. Symptoms were measured repeatedly by the Brief Pain Inventory (BPI) and the M. D. Anderson Symptom Inventory (MDASI). The primary endpoint was to establish the safety, feasibility, and efficacy of using a CT-on-Rails or Trilogy Stereotactic Spine Radiation Therapy system to treat spinal and paraspinal tumors and to document pain relief and toxicity associated with such treatment. Symptom outcomes were estimated according to protocol using descriptive analysis and ordinal regression modeling. This is the final report for the completed enrollment and follow-up.
The median follow-up time was 15·9 (interquartile range 9·5–30·3) months and the mean was 20·9 (SD=17·1) months. The actuarial tumor progression-free survival rates at one year and two years post-SBRT were 80·5% and 72·4%, respectively. Patients reported significant MDASI pain reduction (p=0·00003) during the six months post-SBRT. Patients reporting no pain from bone metastases on the BPI increased from 39/149 (26·2%) before SBRT to 55/102 (53·9%) six months post-SBRT (p<0·0001). BPI pain reduction from baseline to four weeks post-SBRT was clinically meaningful (effect size=0·47, p<0·01). These improvements were accompanied by significant reduction in opioid use during the six months post-SBRT (p<0·05) and a significant reduction in MDASI symptom interference with daily life (p<0·01).. Only a few instances of nonneurological grade 3 toxicities occurred (one report each of nausea, vomiting, diarrhea, fatigue, dysphagia, neck pain, diaphoresis, two reports of pain associated with severe tongue edema and trismus, and 3 reports of noncardiac chest pain). No grade 4 toxicities occurred.
SBRT is an effective primary or salvage treatment of mechanically stable spinal metastasis. Significant reduction in patient-reported pain and other symptoms was evident six months post-SBRT, along with satisfactory progression-free survival and no late spinal cord toxicities.
Keywords: SBRT, pain, symptoms, patient-reported outcomes (PROs), spine, metastasis